This disclosure relates to a metering valve for a fuel metering system.
Gas turbine engines are known, and typically include a compressor that compresses a working fluid, such as air, and delivers it to a combustor. The compressed working fluid is mixed with fuel in the combustor, combusted, and the products of combustion pass downstream over turbine rotors, driving the rotors to create power.
A metering valve provides metered flow to the combustor, provides position feedback to a full authority digital engine controller (FADEC), moves in response to a FADEC command, shuts fuel flow off in response to a FADEC command and provides pressure signals to various fuel system components. Metering valves typically include a central spool surrounded by a sleeve. Apertures in the sleeve selectively allow fuel to flow in cavities defined between the sleeve and the spool. Movement of the spool in one direction relative to the sleeve causes an overlap between the sleeve apertures and the cavity and allows fuel to flow, and movement of the spool in the opposite direction relative to the sleeve may cause fuel flow to be restricted. The spool and the sleeve are kept in contact via dynamic seals and lands.